1. Field of the Invention
The present invention relates generally to wire stripping and, in particular, to stripping polymer coatings from optical fibers.
2. Background of the Related Art
Optical fibers are subject to several forms of impairment when their polymer coatings are removed or stripped. These impairments include tensile strength degradation which decreases an optical fiber's life, and acid or solvent residue which may obscure signal transmission through the optical fiber when spliced.
Prior art methods for removing an optical fiber's polymer coating include mechanical stripping and acid stripping, as the terms are known in the art. Mechanical stripping involves using a stripping tool, which is similar to a wire stripper, to remove the polymer coating from the optical fiber. The stripping tool cuts through the polymer coating and typically nicks or scratches the optical fiber causing degradation in its tensile strength, thereby reducing the optical fiber's longevity. For example, an optical fiber with a tensile strength of 15-16 pounds is typically reduced to 3-5 pounds after mechanical stripping. Minimizing tensile strength degradation is important particularly in situations where high repair costs make longevity a system requirement.
The primary prior art method for removing an optical fiber's polymer coating with minimal degradation in tensile strength is acid stripping using a hot Sulfuric Nitric mixture, i.e., 95% Sulfuric acid and 5% Nitric acid. Specifically, this prior art method involves heating the Sulfuric Nitric mixture to approximately 185.degree. C., immersing the optical fiber in the hot Sulfuric Nitric mixture for approximately 20 seconds, and rinsing the optical fiber for 2-10 seconds in a rinser, such as Acetone, Alcohol, Methanol, purified water, or a combination of these. Although tensile strength degradation is minimized, this prior art method may leave an acid or a solvent residue between spliced optical fibers at the splice point, thereby degrading the tensile strength of the optical fiber at the splice point.
Furthermore, safety concerns are often present with acid stripping methods. Field technicians employing acid stripping methods require well-ventilated areas, such as laboratory environments with exhaust hoods, and protective gear to safeguard themselves from fumes and burns associated with acids. However, such facilities are generally not readily available to the field technicians. Accordingly, there exist a need for a method for removing a polymer coating from an optical fiber in a safe manner while minimizing tensile strength degradation.